Low pleural fluid-to-serum glucose gradient indicates pleuroperitoneal communication in peritoneal dialysis patients: presentation of two cases and a review of the literature.

BACKGROUND: Transudative pleural effusions due to pleuroperitoneal communication occur in 1.6-10% of patients receiving peritoneal dialysis (PD) and usually have overtly elevated glucose concentrations.
METHODS: We report two cases of verified pleuroperitoneal communication with minimally elevated pleural fluid glucose levels. We reviewed the literature of all PD patients with pleuroperitoneal communication that reported pleural glucose levels to assess their clinical and laboratory features and pleural fluid-to-serum glucose gradients.
RESULTS: We evaluated a total of 47 reported patients on PD with diagnosed pleuroperitoneal communication. Onset of the transudative pleural effusion after initiating PD was <3 months in only 48%. Shortness of breath was reported in 96%. Pleural effusions were right sided in 87%. Pleural fluid-to-serum glucose gradients varied from 2 to 1885 mg/dL, with 20% ≤50 mg/dL, 13% being 51-100 and 67% >100 mg/dL. All pleural fluid-to-serum glucose ratios were >1.
CONCLUSIONS: With a transudative pleural effusion in patients receiving PD, a pleural fluid-to-serum glucose ratio >1 is consistent with a pleuroperitoneal communication. In questionable cases, independent verification is necessary.